10 April 2010

Ethernet hub

Definition: In computer networking, a hub is a small, simple, inexpensive device that joins multiple computers together. Many network hubs available today support the Ethernet standard. Other types including USB hubs also exist, but Ethernet is the type traditionally used in home networking.

Working With Ethernet Hubs

To network a group of computers using an Ethernet hub, first connect an Ethernet cable into the unit, then connect the other end of the cable to each computer's network interface card (NIC). All Ethernet hubs accept the RJ-45 connectors of standard Ethernet cables.

To expand a network to accommodate more devices, Ethernet hubs can also be connected to each other, to switches, or to routers.

Characteristics of Ethernet Hubs

Ethernet hubs vary in the speed (network data rate or bandwidth) they support. Some years ago, Ethernet hubs offered only 10 Mbps rated speeds. Newer types of hubs offer 100 Mbps Ethernet. Some support both 10 Mbps and 100 Mbps (so-called dual-speed or 10/100 hubs).

The number of ports an Ethernet hub supports also varies. Four- and five-port Ethernet hubs are most common in home networks, but eight- and 16-port hubs can be found in some home and small office environments.

Older Ethernet hubs were relatively large in size and sometimes noisy as they contained built in fans for cooling the unit. Newer devices are much smaller, designed for mobility, and noiseless.

When To Use an Ethernet Hub

Ethernet hubs operate as Layer 2 devices in the OSI model, the same as network switches. Although offering comparable functionality, nearly all mainstream home network equipment today utilizes network switch technology instead of hubs due to the performance benefits of switches. A hub can be useful for temporarily replacing a broken network switch or when performance is not a critical factor on the network.

source : about.com

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